Biopsies are often indispensable tools for accurate diagnosis and/or staging of a disease as blood-based tests typically provide only indirect evidence of tissue status, and current imaging analysis often lacks sufficient resolution and information density.
Most commonly, a biopsy is performed using a biopsy gun in which one or more needles are advanced into the target tissue, typically under ultrasound or MRI guidance. A typical biopsy needle and gun is described in U.S. Pat. No. 5,971,939. Where desired, sample acquisition and movement may be assisted using vacuum in the needle as illustrated in U.S. Pat. No. 5,027,827. These and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Furthermore, where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. A core of tissue is then removed along with the biopsy needle, and the core is immersed in a fixative or frozen after removal from the needle.
The core is subsequently embedded in paraffin and cut, or cryo-sectioned for mounting on a microscope slide prior to staining, nucleic acid analysis, or other analysis. Unfortunately, the processing steps for visual analysis of tissue (e.g., fixation, paraffin embedding, and staining) and molecular biological analysis of tissue (e.g., in-situ PCR, fluorescence in-situ hybridization, etc.) are in many cases incompatible and thus require multiple tissue samples to be taken from the area under investigation.
Multiple-sample biopsies can be performed in numerous manners using certain devices and methods known in the art. For example, U.S. Pat. No. 5,415,182 describes a biopsy gun in which an array of needles is fired into the suspect tissue. Alternatively, as disclosed in EP 1 545 318 B1, a single biopsy needle has a plurality of separate sample cavities to allow sampling in multiple locations. In still further known devices, multiple radially arranged windows in a cannula in conjunction with an internal cutter are used to generate a plurality of samples in proximal location to each other as taught in U.S. Pat. No. 5,944,673. Alternatively, multiple samples in relative proximity can be obtained using a system in which a cannula has multiple openings and in which a spiral blade is advanced to section the samples from the tissue as described in U.S. Pat. No. 6,530,891. While such devices advantageously allow collection of multiple samples from a single area, various disadvantages nevertheless remain. For example, where a malignancy is relatively small or distributed irregularly across a tissue (e.g., various malignancies in the prostate), the collected samples often fail to be co-located in the same area of interest. Therefore, the above devices often fail to provide consistent and representative samples.
The same difficulties exist in still further known devices where multiple biopsies can be taken serially through a single sample window or needle with a flexible retractable tip cover as disclosed in U.S. Pat. No. 6,149,607 and WO2007/021903A2, and U.S. Pat. No. 7,137,956, respectively. While such devices allow collection of multiple samples in multiple areas of interest, samples produced with these devices typically fail to produce tissue of the same area of interest.
To overcome at least some of the difficulties associated with multiple samples from the same area, certain biopsy devices have been described in which a sample is cut from the tissue of interest via a cannula or needle in which the tissue is further sectioned as the cannula or needle advances. For example, FIG. 6 in U.S. Pat. No. 5,823,971 illustrates a cannula in which a cutting wire is placed across the front cutting edge of a round cannula. In such devices, the tissue core is split in the cannula as the cannula advances and cuts the core from the tissue via rotation. Similarly, U.S. Pat. App. No. 2008/0114265 teaches an open-ended needle tip that cuts a cylinder of tissue as the needle advances through the tissue. An internal separator structure then splits the cylinder and maintains the split products in separate cavities from which they can be removed by removing an outer cover sheath that covers the cavities when the needle is inserted into the area of interest. While such devices and methods at least conceptually produce two samples from the same location, numerous difficulties nevertheless remain. Most significantly, as the tissue is forced through the lumen of the cannula or needle, tissue distortion due to friction along the inside of the cannula or needle, and/or compression due to the added volume of the blade/separator structure will occur and lead to loss of tissue and tissue integrity, which is particularly pronounced in the device of the '265 application as the inner lumen is significantly smaller than the cutting tip lumen.
In an attempt to avoid such drawbacks, a biopsy core can be split after removal from the needle in longitudinal direction before processing. However, such post-harvest splitting requires considerable expertise and equipment typically not available in the clinic at which the biopsy is taken. Moreover, even where great care is taken to split the biopsy core equally, consistent splitting is rarely achieved throughout the entire length of the core.
Therefore, while numerous devices and methods for biopsies are known in the art, all or almost all of them suffer from one or more disadvantages. Most significantly, correlation of the corresponding areas is typically not possible as non-adjacent surfaces are generally obtained in such devices and methods. Consequently, there is still a need to provide improved devices and methods for biopsies.